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<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  

  <script>
    let arr=[1,2,3,4]
    function odd(array) {
     
      let sum=0
      let flag=0
      for(let i=0;i<array.length;i++){
        if(array[i]%2===1) {
          sum+=array[i]
          flag=flag+1
        }
      }
      return sum/flag
      // return 0
      // /不知道如何将0输出/ 

    }
   console.log( odd(arr));
  </script>
  
</body>
</html>